Coupling apparatus



March 1958 c. REYKJALIN 2,825,437

COUPLING APPARATUS Filed Sept. 7, 1954 United 2,825,437 COUPLING APPARATUS Application September 7, 1954, Serial No. 454,300

14 Claims. (Cl. 192-105) This invention relates to improved coupling apparatus and more particularly to an improved device for coupling two rotatable elements in fixed angular relationship within predetermined limits of speed and torque.

It is one principal object of this invention to provide an improved coupling device which will disengage under the influence of excessive loads applied over prolonged periods of time and which will also be responsive to speeds and torques within predetermined ranges. Various devices have been proposed heretofore which were designed to couple a driving shaft to a rotatable load. Such devices have featured one or more of the characteristics inherent in this invention, but none has been taught which has all of the desirable characteristics of the instant invention. The characteristics required in certain applications for which the instant invention is especially well adapted include a coupling of the motive means to the associated load for speeds above a predetermined minimum, decoupling of the motive means from the load for torques in excess of a predetermined maximum and a complete disengagement of the coupling means for excessive loads over a predetermined prolonged period of time. i

The first characteristic is desirable in order to use a motive means of limited torque which will have sufficient starting inertia to rotate the load when the coupling means engages. The second and third characteristics of the coupling means protect the motive means from damage when excessive loads are experienced. Devices heretofore proposed for accomplishing these aims have included various centrifugal devices for speed sensitivity and such means as shear pins, overload circuit breakers and the like for excess torque and load protection. However, such devices have proven generally unsatisfactory as they do not provide for easy re-establishment of power to the load, are not sufiiciently sensitive to the torque and load being transmitted or the duration of a prolonged overload and are also expensive and cumbersome devices not readily repaired after experiencing an overload condition.

It is therefore a further object of this invention to provide an improved coupling device which is actuated only at speeds above a predetermined minimum and which is deactuated for torques and load above a predetermined max mum. 7

It is another object of this invention to provide an improved coupling device which permits slippage between driving and driven members during an initial starting period; through which the members become firmly engaged to prevent slippage during normal torque transmissions; and which will be dis-engaged upon a prov longed application of excess torque.

It is still another object of this invention to provide an improved coupling device which is speed and torque sensitive and which has a thermally sensitive permanent disengaging element to prevent excessive heating or damage to the parts thereof for torques in excess of the designed range of the device.

It is another object of this invention to provide an improved overload protection for a coupling device by tes Patent Ftce which heat is transmitted from a slipping element to a contiguous thermally sensitive element comprising a pair of fused annular rings.

It is still a further object of this invention to provide a thermally fusible element for a coupling device which has a large fusible area to provide high sensitivity while maintaining good torque transmitting characteristics.

It is a further object of this invention to provide a speed and torque sensitive coupling device having thermally fusible overload protection, said protection being a replaceable element which may be easily stocked by a user or repaired on the job under emergency conditions.

Further and additional objects of this invention will become manifest from a consideration of this specification, the accompanying drawings and the appended claims.

In one form of this invention a lubricant filled centrifugal clutch is provided in which the input member is a rotatable shaft having a plurality of radially movable clutch elements with wedge-shaped surfaces adapted to engage correspondingly shaped surfaces in a housing comprising the driven member. The driven member is coupled to anIoutput member through a pair of annular rings, one of which is keyed to the driven member and the other of which is keyed to the output member, said annular rings having congruent annular surface portions which are juxtaposed and secured together by an appro ing wherein: r Fig. 1 is an axial sectional view of one embodiment of this invention;

Fig. 2 is a transverse sectional view of the embodiment of Fig. l, takenon the line 2-2 thereof with portions of the driven housing removed;

Fig. 3 is a top plan view of the element of the embodiment of Fig. 1;

Fig. 4 is a bottom plan view of the output element of the embodiment of Fig. 1; and

Fig. 5 is a perspective view of the thermally sensitive element shown in Fig. 3.

Referring now to the drawing and more particularly to Fig. 1, a coupling device 10 is illustrated which is both speed and torque sensitive and also has protective features to insure againstprolonged overloading of the motive means. A motive means 12 has an output shaft 14 to which the coupling device 10 is secured and a sheave 16 forming a part of the coupling device 10 is engaged by a conventional V-be'lt 18, which may drive any rotatable load in the well understood manner. The cou- 'pling device 10 comprises a central hollow shaft 20 which is secured to the motor shaft 14 by a collar. 22 having a set screw 24 threadably engaged therein and in abutting engagementwith the shaft 14. The set screw 24 passes through an appropriate aperture 26 in the hollow shaft 20.

A plurality of pins 28 extend radially from the outer end of thehollow shaft 20 and are threadably secured i therein to'form a spider-like assembly. In the particular embodiment illustrated six such pins extend outwardly from the shaft 20 as illustrated more clearly in Fig. 2.

the associated .pin 28 whereby the weight is freely mov able radially thereon. The spider and weights are dis posed within a housing 34 which comprises the driven member. The housing has generally convergent sides and t as illustrated in the drawing is assembled from two coop- Y crating sheet metal elements .36 and .38; annular thermally sensitive have fannularfiac esifcorresponding;iokthezaangularlyddi posedqsurfacesaofzthehousing iskwherehysrotationaofsthe 5 driving spider will efiect radial movementiofzfhemeightsiir 30 andwconsequentzengagernent oirfthezangtilar smaeee 1 with the innerv;surfaces of: the housing- 34 of pads 4 2; 'ar'eprovided; on each; weight 'fsflitozsinsur eugood 'A plurality frictional lcontact between teachzweight ,and: the'housingvlo walls; The; pads' mayrbe l.of any appropriate. material having the zdesirecl'frictionakandzweancharacteristics a1 though "an impregnatedofibertconstruction :hasgbecnefdund especiallyi-wellradapted for {this purpose; The pads-042 j i are=preferably=rcemented into; appropriate:depressions im 5 the:;weights;30.-;;.l 1'; 1 o o r o -Theflhousingsfid is;partially::filled with allubricantzifl to provideopredetermined slippage eharacteristicsbetween V the weights and the housing. Upon initial actuation of s the device the lubricant is splashed about withingthe hous i 20 o inggproviding a low. frictional -engagement3between 'the 5; pads 42 and the housingMAsQthe housing begins to ro- 'tate, however; thef lubricant therein is 1 forced 4 outwardly- "by centrifugal forcetoofillzthe'a'rea 46 about the periphery of the-housing sum the pads 42 will quickly be wiped Z1125 substantially: free of lubricant whereby a'rigid frictional g:

' engagement-is provided the couplingi thereby being tfree of slippagegfornnorrnal torque transmission. While: the V luhrica'ntoishownin;thiszembodiment is a conventional lu bricatingoil,- various lubricatingoilsor certaini p owdered or comminuted lubricants may also-beusedrhereinr The=;h0using 34, is mounted-on the jhollow 'shaft 20 with=a bearingmaterial. 48 disposedtherebetween. Upon initial actuation of the device'there will be 'relative rotai 7- tiontbetw'eenithe cylindrical shaftz ZO and the housing-34 5 but after the hoiising reaches full speed, the elements lwill' function'asoan integral unit; The-outputc-sheave-il6 is composed of two sheet metali-felementslsfland 52 secured, together, as by welding,s'to forma V-shapedre normally :secured against ceiverforth'beltiS- The sheave 50 is rotatably fmounton the housing'34 through bearingmaterial-Sd bug 1:: 7. n rotation with respect uto the h ng. 7

"5A: oedangular-relationship isestabli shedj between the housing 34 and the sheave 16 throughathermallysensi -o t1ve 's'assembly-r56. aTheassemlrllyt 56 include'salring sfi mentaby; inwardly tdisposed-detents'i62rangularly formed fromzithe; sheaye element:52. The L second annulart ring 641s secm'edstoihe annulanring 58:by an insert or 9 V means onezof;said,ringsebeing connected 'to eachuof sai f 68 tormed: therein awhi'ehtisi-noimally 'engaged by a lug V V 70 rigidlyi-secured tokthe housing 34. -It am n-made Y 'cient frictiomandithe'timeduration is'relativelyshort; ,7 The lntch or-c'oupling device-taught by;this:invention 'main be reconditio'tied readily fof-additionalmse following v agthermal release bythe removal ofihsetscrew 24*a'nd the'rjeplacjement-of the separated annular rings 58 and 64 made, new

T 1 iencedduring the starting portion of an operating cycle obe'caus thersplashinglubric'ant maintains alow coe havingffonz notchesofl peripherally disposed-for enga'geof'fusiblematefial 266. Thering 64, has a' singlegnoteh that :power is transmitted from the housing 34 man e rienced: bygthe device, slippa'geioccurs between the driving spider and th'e'd riven housing to generate substantial heat;

motive-means} The excessive heating will-not be expee o fused=ringsinaterial used4o "secureg V .thearingsitogetherflmaybe means-mounted on saidtdriven means, first annular-mean detachIhIyfiXed; to. saiddriven-ameansofor rotation ther "fotatableo drivingmeans a coaxial rotatable driven means,

; q 7 V4 4 N V V V anytzonewoi many well fusible materials, although alloys of tin, lead and bismuth function especially well in'this capacity. The alloygse: V lected will depend upon the temperature at which release 7 is desired. One particular alloy of lead and tin which was employed in the described embodiment becameplastie at 250 which may be attainedin a short period of time when the devicetis ex e -iencin ea substantial.

rload, at ,7

While'ione particular embodiment has beenfdescri in detail, various combinations. of rel'ern'ents'fqwill; ooc'gr to, one skilled in the art which will a ccomplish'the desired ends and- --objectstaught herein and all of. thesecombin ations are believed clearly-Mthin1thespirigand scope of: thisinvention. Poi-example, thesheave and housing of the described embodiment'are formed of sheet inetaL to' produce an inexpensive and light weight device. .How

everfithese-elenients :may .be past .or machined :for greater? precision where accurate limitations imustibe maintained Without further :elaboration,tthe .foregoinglwilll'soiully; explain the character'iof my invention that .others, .may; by sapplyinggcurrent knowledge; readily: adapt thei sam i for use'uundervarying conditions of service;v while retainingtcertain. features 7 which may. properly be; said to::con stitutestheessentialitems :of novelty involved, which item aregintendedlto begdefin'ed; andxse cured tozme :by the fo l. iAlzcoupling device." comprising arirotatablefldrivin means;- a coaxial "rotatable drivene means, cfriction'imeans connecting; said driven and/saiddriving means; outp with; and; second; annular means. detachably fixed. to sai output lmea'ns for =rotation therewith; said firsttaifdise ond; annular, meansobeing" juxtaposed andsfusedatogethe by fthermally, sensitive means :and qr emovablei asma 311m from; said device, saiddriyen means and said} output mean 'being ."freely; rotatable arel'atiyely lwheneven said thermall sensitive means is heated V permitting separation; of sai firstzandosecond annular mea s, 7 J V a ;A *torquet sensitive; coupling. device @comp risingfrictiongmeans connecting said' gdriven and tsaidi driving means, output-means t.coaxially imounted relative -f-togsai driven ;.means;: and; Lthen'nallylsensitive -means interco 'necting; said 'outputmeansii and .saiddriven -rnea1is' "in 1 fixedmngulartrelationship;isaid -thermally sensitive' means lcomprising'ia pair; of'ering's 'having cong'ru'ent annular sur faceerportionszv'securied together;by; thermally f sensitiv output Lme'ans'tand i said driven meansigsa'id dr" en me lativel thelugflfl;thegannularringfiflthering-58 whichisj secured 5 to the fing3i64zbyg fusible"matreial, andthe sheave--1 6Mb the-outputib elt 218;:ilf, however; excessive torque is' Xpe:

' faceiportions andiaithermall driven means, and thermally sensitive means interconnecting said output means and said driven means in a fixed angular relationship, said thermally sensitive means com-.

prising a first annular ring keyed to said driven means, a second annular ring keyed to said output means, said first and second rings having congruent annular portions in juxtaposed relationship, and a thermally fusible ma terial disposed between said congruent portions and securing said portions together said driven means and said output means being freely rotatable relatively whenever said thermally fusible material is heated, permitting separation of said annular portions.

5. A torque sensitive coupling device comprising a rotatable driving means, a coaxial rotatable driven means, friction'means connecting said driven and said driving means, output means coaxially mounted relative to said driven means, and thermally sensitive means interconnecting said output means and said driven means in a fixed angular relationship, said thermally sensitive means comprising a first annular ring keyed to said driven means and in intimate thermal contact with said friction means, a second annular ring keyed to said output means, said first and second rings having congruent annular portions in juxtaposed relationship, and a thermally sensitive fusible metal disposed between said congruent portions and securing said rings together, said rings comprising a replaceable protective unit said driven means and said output means being freely rotatable relatively whenever said thermally fusible metal is heated, permitting separation of said annular portion. 7

6. A torque sensitive coupling device comprising a rotatable driving means, a coaxial rotatable driven means, friction means connecting said driven and said driving means, output means coaxially mounted relative to said driven means, thermally sensitive means interconnecting said output means and said driven means in a fixed angular relationship, said thermally sensitive means comprising protuberance means extending from said driven.

means, a first annular ring having aperture means in engagement with said protuberance means, second protuberance means extending from said output means, a second annular ring having aperture means in engagement with said second protuberance means, said first and second rings having congruent annular portions in juxtaposed relationship, and a thermally sensitive fusible material disposed between said congruent portions and securing said rings together said driven means and said output means being freely rotatable relatively whenever said thermally fusible material is heated, permitting separation of said annular portions.

7. A speed and torque sensitive coupling device comprising a rotatable driving means, a coaxial rotatable driven means, centrifugally actuated friction means connecting said driving and said driven means, output means coaxially mounted relative to said driven means, and thermally sensitive means interconnecting said output means and said driven means in a fixed angular relationa ship, said thermally sensitive means comprising a first annular ring keyed to said driven means and in intimate thermal contact with said friction means, a second annular ring keyed to said output means, said first and second rings having congruent annular portions in juxtaposed relationship, and a thermally sensitive fusible metal disposed between said congruent portions and securing said rings together, said rings comprising a re-' placeable protective unit said driven means and said output means being freely rotatable relatively whenever said thermally fusible metal is heated, permitting separation of said annular portions.

8. A speed and torque sensitive coupling device com prising a rotatable driving means, a coaxial driven housing enclosing said driving means, centrifugally actuated friction means carried by and radially movable relative to said driving means, said friction means engaging said driven housing at a predetermined speed, a lubricant partially filling said housing, contacting said friction means for all speeds below said predetermined speed and displaced therefrom by centrifugal force for speeds above said predetermined speed, output means coaxially mounted relative to said driven housing, and thermally sensitive means interconnecting said output means and said driven housing in fixed angular relationship, said thermally sensitive means comprising a thermally sensitive material and a pair of rings having congruent annular surface portions secured together by said thermally sensitive material said driven housing and said output means being freely rotatable relatively whenever said thermally sensitivev material is heated, permitting separation of said annular portions. 7

9. A speed and torque sensitive coupling device comprising a rotatable driving means, a coaxial-driven housing enclosing said driving means, centrifugally actuated friction means carried by and radially movable relative to said driving means, said friction means engaging said driven housing at a predetermined speed, a lubricant partially filling said housing, contacting said friction means for all speeds below said predetermined speed and displaced therefrom by centrifugal force for speeds above said predetermined speed, output means coaxially mounted relative to said driven housing, and thermally sensitive means interconnecting said output means and said driven housing in fixed angular relationship, said thermally sensitive means comprising a first annular ring keyed to said driven housing and in intimate thermal contact with said friction means, a second annular ring keyed to said output means, said first and second rings having congruent annular portions in juxtaposed relationship, and a thermally sensitive fusible metal disposed between said congruent portions and securing said rings together,'said rings comprising a replaceable protective unit said driven housing and said output means being freely rotatable relatively whenever said thermally sensitive metal is heated, permitting separation of said annular portions.

10.A torque sensitive coupling device comprising a rotatable driving shaft, a coaxial driven housing partially V enclosing said shaft and providing a sealed enclosure, said housing having a pair of opposed convergent generally conic surfaces extending outwardly from said shaft, a plurality of clutch weights angularly disposed about said shaft and radially movable relative thereto, said clutch weights having radially convergent surfaces corresponding to the convergent surfaces of said housing whereby centrifugal force effects engagement therebetween for driving shaft speeds above a predetermined minimum, a lubricant partially filling said enclosure, output means coaxial relative to said housing, and thermally sensitive means interconnecting said output means comprising a thermally sensitive material and a pair of rings having congruent annular surface portions secured together by said thermally sensitive material said driven housing and said output means being freely rotatable relatively whenever said thermally sensitive material is heated, permitting separation of said annular portions.

11. A torque sensitive coupling device comprising a rotatable driving shaft, a coaxial driven housing partially enclosing said shaft and providing a sealed enclosure, said housing having a pair of opposed convergent generally conic surfaces extending outwardly from said shaft, a plurality of clutch weights angularly disposed about said shaft and radially movable relative thereto, said clutch weights having radially convergent surfaces corresponding to the convergent surfaces of said housing whereby centrifugal force effects engagement therebetween for driving shaft speeds above a predetermined minimum, a lubricant partially filling said enclosure, output means coaxial relative to saidhousing, and a thermally sensitive means interconnecting said output means and said housing in a fixed angular relationship, said thermally sensitive means comprising a first annular ring I keyedf'to said' drivenflhousing amlfin intimate fethrm V rotatable drivin'g shaft; afcoaxial driveni'h tially enolosing' said shaft; and providing 7 1 closure,r said housinghaving a pairofopposejd oo'nyergent 15 7 about said sliaftoand radially-movablejrelat output means coaxial relatiyeto' said housin' annular rings, on sa'iddfiyen housing andija the sensitive; means interconnebting' said vo1'1tp11t,1'1'1'e2 1n rotatable relatively whene ersaidthermally sensitiy mettionsgq' a V a to V i 'cont actjwithf'saidqfriotiong means,. ja is'econdjannular; ring I fiit z daoum tlmea d ta d lsel having congruem annular portions in juxtaposed vrela -i 7 tionshipganda thermally sensitivegfusibleifietalfdisposd 5 between ;sai d congruent portions and seeuring'fsajdrings togethelg'said ringswcomprisi'ng a replaoeabl proteotive' unitsaid dr'iyen housing and saiclo itpnt jneans being 1 freely; rotatable relatively When'eyensaid jtherr'pallygsensi tive' metal is heated, permitting separation iiof :said an- 10' nular portionsf 7 a y a a it 12;A torque sensitive couplingfdeyieejcomprising i I sin spar." qsealed engenerally fconic' 'surfaes extending "outwardly fi om said shaft; a plurality ';of clutch weights 'a g lat said clutch?weights havin radially eo'nverg corresponding to the convergent lsurfaces of '5 whereby centrifugal force effects engagem tween fofdriVing rshaft speedsfabov'e .a pre'd 7 V a minimum, a' lubricant partially. fillings saidjenolosure;

means r'emovably maintaining said outpu t'mea'ns,

said housing 'in, la a fixed angular"relationshipisaid fli mallyfsensitivimeans comprisin'gla jfii'stTannul r7 a1 is h e permit in p at o f? d an ula I sensitiyeimeans imetoonnegting saidjrotatable meansfand said'youpling mean n a fixedangular-relationship,;said I Qr u a i e 'coup in :d v e m ms fli iw xia zr ta @q nj .izi in ,m ans: znnt d isl -i at; 1 dmtata z mea s; up pamea zia lv L r saidim atabl in a san m lly i fixed ito said :rotatable ineansfvsaid."first and second; an; I

nular meanybeing fusedibyitl ermallysensitive material d emczvah s a tatnn t i msa means;a nd ai go'upling relatively h t d;

U S. DEPARTMENT OF COMMERCE PATENT OFFICE CERTIFICATE OF CQRRECTION Patent No 2i;g825,43'7 March 4, 1958 Charles Reykjalin It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Let sers Patent should read as corrected below.

Column 3;, line 56, for mavbreial" read material column 5, line 30, for "portion" read portions column '7, line 37, after "housing" insert and e Signed and sealed this 22nd day of April 1958,

( SEAL) Attest:

KARL HO AXLINE ROBERT c. WATSON Atteating Officer Con-missioner of Patents 

